Interpretive Summary: Sunn hemp (Crotalaria juncea L.) is the fastest growing species of the genus Crotalaria and is the most widely grown green manure in the tropics. Sunn hemp is also adapted to a wide range of conditions and soil types, while still producing high biomass yields. These characteristics enable the crop to be used as a summer cover crop to protect and conserve soil and improve soil productivity. However, sunn hemp can only produce seed in tropical environments, which results in limited seed supplies and high seed costs. Auburn University recently released two sunn hemp cultivars, ‘AU Golden’ and ‘AU Durbin’, capable of producing seed in subtropical/temperate climates of the U.S. General agronomic information on sunn hemp production, management, and uses are summarized in this publication from a wide range of contributors that include Auburn Univ. scientists, ARS scientists in Auburn and Booneville, as well as, Heifer International in Arkansas.

Technical Abstract:
Sunn hemp (Crotalaria juncea L.) is the fastest growing species of the genus Crotalaria and is the most widely grown green manure in the tropics. Sunn hemp is also adapted to a wide range of conditions and soil types, while still producing high biomass yields. These characteristics enable the crop to be used as a summer cover crop to protect and conserve soil and improve soil productivity. However, sunn hemp can only produce seed in tropical environments, which results in limited seed supplies and high seed costs. Auburn University recently released two sunn hemp cultivars, ‘AU Golden’ and ‘AU Durbin’, capable of producing seed in subtropical/temperate climates of the U.S. General agronomic information on sunn hemp production, management, and uses are summarized in this publication.